i 4 6 HISTORr of the SOClETr. 



All the Solutions of Strontites in acids are decompofed by 

 the three alkalies in their effervefcent ftate, and in part by vir- 

 tue of a double elective attraction. The artificial carbonate of 

 Strontites thus obtained, parts with its fixed air more readily 

 than the native. Pure potafs feparates Strontites from nitric 

 and muriatic acids, but partially, and in a cryftalline form. 

 Neither prufliate of potafs nor of lime caufe a precipitate in any 

 of the folutions. 



Strontites generates a hepar with fulphur either in the hu- 

 mid or dry way. Tts cryftals are fparingly diflblved by alco- 

 hol ; a yellow coloured tincture refults. 



After finihing the detail of the properties of the Strontian 

 mineral and its earthy bafts, Dr Hope proceeds to enquire, whe- 

 ther this foflil and its earth are fimilar to any that are already 

 known. He concludes they are not. Strontian fpar refembles 

 moft the aerated terra ponderofa, and in feveral refpects has a 

 ftrong analogy with it; yet it eflentially differs. 



Its fpecific gravity is lefs, it parts with its carbonic acid 

 when urged by heat, fomewhat more readily, and without fuf- 

 fering fufion ; when calcined, it imbibes moifture with vaftly 

 greater avidity, fwelling and cracking with more heat and 

 noife- Strontites diflblves much more abundantly in hot wa- 

 ter than barytes, and the form of the cryftals of thefe pure 

 earths is very diftimilar. The compounds generated by Stron- 

 tites differ from thofe of barytes. It will fuffice to mention 

 the nitrate and muriate. This earth, united to nitric and mu- 

 riatic acid, forms falts that fuffer changes from expofure to air, 

 which do not happen to the nitrate and muriate of barytes. 

 They are likewife much more foluble in water, and have cry- 

 ftals of a peculiar figure. 



The combinations of Strontites with acids are not, like thofe 

 of barytes, decompofed by pruffiate of lime or of potafs. 



Strontites 



